Galeacysta etruscacomplex: Dinoflagellate cyst marker of paratethyan influxes to the Mediterranean sea before and after the peak of the messinian salinity crisis

Abstract

2009) Galeacysta etrusca complex: Dinoflagellate cyst marker of paratethyan influxes to the Mediterranean sea before and after the peak of the messinian salinity crisis, Palynology, 33:2, 105-134, AbstractMore than one thousand specimens of a morphological complex including Galeacysta etrusca Corradini & Biffi 1988 from 11 Upper Miocene and Lower Pliocene localities of the Paratethyan and Mediterranean realms have been studied using a biometric approach in part relating to the degree of separation between endocyst and ectocyst. Four stable biometric groups have been distinguished statistically, the occurrence or prevalence of which appears closely linked to environmental conditions irrespective of the realm. Group 'a' is related to brackish conditions, group 'b' to marine conditions, group 'c' to freshwater, and group 'd' to high nutrient levels. Based on an accurate chronology provided by calcareous nannoplankton bioevents and recognition of the Messinian Erosional Surface, this study reveals:Palynology, 33 (2) 2009:105-134 Downloaded by [Northeastern University] at 17:47 01 December 2014 106 PALYNOLOGY, VOLUME 33(2) -2009(1) the high sensitivity of the Galeacysta etrusca complex for reconstructing paleoenvironments and discriminating phases of connection and isolation of basins;(2) the detailed history of this species complex which originated in the Pannonian Basin at ca. 8 Ma before invading the Dacic Basin during the interval 6-5.60 Ma, then migrating into the Mediterranean during high sea-level connections (the 'Lago Mare' events just before and after the peak of the Messinian Salinity Crisis, i.e. at 5.60 Ma and during the interval ca. 5. respectively), and finally into the Black Sea at ca. 5.13 Ma;(3) an improved paleogeography for the Mediterranean and Paratethyan realms with focus on the location of corridors and the timing of when they were active.Based on field observations and dinoflagellate cyst data, we propose that the reflooding of the Mediterranean Basin by Atlantic waters occurred at ca. 5.46 Ma, about 130 kyr before the Zanclean GSSP (5.332 Ma).

Migration of the dinoflagellate Galeacysta etrusca and its implications for the Messinian Salinity Crisis

“…Arenazzolo Erosion Clauzon et al, 2005Clauzon et al, 1996Popescu et al, 2015Popescu et al, 2009Do Couto et al, 2014 Lower Evaporites…”

“…Moreover, the Arenazzolo Formation of Sicily is considered to resemble the uppermost part of Upper Evaporites just below the Mio-Pliocene transition (sensu Manzi et al 2009). Some studies claim an unconformity at the base of the Trubi (Clauzon et al 1996) or Arenazzolo Formation (Clauzon et al 2005, Popescu et al 2009, 2015, Do Couto et al 2014. The distinction of 2 to 3 different Lago Mare events is primarily based on the presumed hiatus at the base of the Arenazzolo Fm.…”

“…Regardless of the underlying mechanism, the Lago Mare is also considered to comprise multiple discrete spilling events (Fig. 2;Clauzon et al 2005, Popescu et al 2009, Suc et al 2011, Bache et al 2012, Do Couto et al 2014, Popescu et al 2015. In this perspective, the presence of G. etrusca (and other Paratethyan taxa) could be used to trace different spilling events of the Paratethys into the Mediterranean.…”

“…Interestingly, the Pannonian Basin and the Mediterranean Basin were not directly connected during the MSC, so this species must have migrated through other basins before reaching the proto-Mediterranean Sea. The First Occurrences (FOs) of G. etrusca have already been used to reconstruct a migration path for this taxon (Popescu et al 2009). According to this study, G. etrusca reached the Mediterranean via the Dacian Basin and not via the Black Sea as they assumed the Black Sea to be desiccated during the MSC.…”

“…eschweizerbart_xxx Magyar et al 1999a, Popescu et al 2009, Grothe et al 2014 with new palynological data from the Dacian and Caspian basins to propose a new and straightforward migration path for G. etrusca. Furthermore, careful revision of the occurrences of G. etrusca' in the central and northern Mediterranean allows us to critically review the Lago Mare event(s) of the MSC.…”